Shut-off valve testing system

Abstract

The shut-off valve testing system provides for the testing of the main shut-off valve of a combustible gas supply line in such facilities as refineries, factories, or other plants utilizing such gaseous fuel. The system includes a double-ended hydraulic cylinder receiving hydraulic pressure from a suitable source, the cylinder communicating hydraulically with a hydraulic actuator for the main shut-off valve. The system provides for testing of the shut-off valve by actuating the valve through a portion of its full travel, thus confirming that the valve is free. This is accomplished by shutting off the pressure to one side of the double-ended hydraulic cylinder, and opening the hydraulic line between the cylinder and the actuator. Thus, hydraulic pressure from the actuator can bleed to the cylinder, allowing the actuator to move to the extent of the limiting spring and/or hydraulic pressure to the opposite side of the cylinder.

I claim: 
     
         1 . A shut-off valve testing system, comprising:
 a hydraulic control cylinder having an actuator volume, a return volume, and a piston therebetween;   a differential pressure transmitter communicating with the actuator and return volumes of the hydraulic control cylinder; and   a hydraulic actuator selectively communicating hydraulically with the actuator volume of the control cylinder, the hydraulic actuator having a loading pressure volume, an actuating pressure volume, and a piston therebetween, the hydraulic actuator further communicating with and controlling a main shut-off valve.   
     
     
         2 . The shut-off valve testing system according to  claim 1 , further comprising a computerized control system communicating electronically with the differential pressure transmitter. 
     
     
         3 . The shut-off valve testing system according to  claim 1 , further comprising a main shut-off valve installed in series in a combustible gas delivery line. 
     
     
         4 . The shut-off valve testing system according to  claim 3 , further comprising a closure limit switch, an open limit switch, and a partial travel limit switch disposed between the hydraulic actuator and the shut-off valve. 
     
     
         5 . The shut-off valve testing system according to  claim 1 , further comprising:
 a first hydraulic valve disposed between the actuator volume of the control cylinder and the hydraulic actuator;   a source of hydraulic pressure communicating with the return volume of the control cylinder;   a second hydraulic valve disposed between the source of hydraulic pressure and the return volume of the control cylinder;   a source of hydraulic pressure communicating with the loading pressure volume and the actuating pressure volume of the hydraulic actuator;   a third hydraulic valve disposed between the source of hydraulic pressure and the actuating pressure volume of the hydraulic actuator;   a hydraulic reservoir communicating with the actuating pressure volume of the hydraulic actuator;   a fourth hydraulic valve disposed between the source of hydraulic pressure and the hydraulic reservoir; and   a fifth hydraulic valve disposed between the actuating pressure volume of the hydraulic actuator and the hydraulic reservoir.   
     
     
         6 . The shut-off valve testing system according to  claim 5 , wherein the hydraulic valves are electromechanical solenoid valves. 
     
     
         7 . The shut-off valve testing system according to  claim 5 , wherein the second hydraulic valve is a three-way valve. 
     
     
         8 . A shut-off valve testing system, comprising:
 a hydraulic control cylinder having an actuator volume, a return volume, and a piston therebetween;   a control cylinder condition transmitter disposed with the control cylinder;   a hydraulic actuator selectively communicating hydraulically with the actuator volume of the control cylinder, the hydraulic actuator having a loading pressure volume, an actuating pressure volume, and a piston therebetween, the hydraulic actuator further communicating with and controlling a main shut-off valve; and   a computerized control system communicating electronically with the control cylinder condition transmitter.   
     
     
         9 . The shut-off valve testing system according to  claim 8 , wherein the control cylinder condition transmitter comprises a differential pressure transmitter communicating with the actuator and return volumes of the control cylinder. 
     
     
         10 . The shut-off valve testing system according to  claim 8 , further comprising a main shut-off valve installed in series in a combustible gas delivery line. 
     
     
         11 . The shut-off valve testing system according to  claim 10 , further comprising a closure limit switch, an open limit switch, and a partial travel limit switch disposed between the hydraulic actuator and the shut-off valve. 
     
     
         12 . The shut-off valve testing system according to  claim 8 , further comprising:
 a first hydraulic valve disposed between the actuator volume of the control cylinder and the hydraulic actuator;   a source of hydraulic pressure communicating with the return volume of the control cylinder;   a second hydraulic valve disposed between the source of hydraulic pressure and the return volume of the control cylinder;   a source of hydraulic pressure communicating with the loading pressure volume and the actuating pressure volume of the hydraulic actuator;   a third hydraulic valve disposed between the source of hydraulic pressure and the actuating pressure volume of the hydraulic actuator;   a hydraulic reservoir communicating with the actuating pressure volume of the hydraulic actuator;   a fourth hydraulic valve disposed between the source of hydraulic pressure and the hydraulic reservoir; and   a fifth hydraulic valve disposed between the actuating pressure volume of the hydraulic actuator and the hydraulic reservoir.   
     
     
         13 . The shut-off valve testing system according to  claim 12 , wherein the hydraulic valves are electromechanical solenoid valves. 
     
     
         14 . The shut-off valve testing system according to  claim 12 , wherein the second hydraulic valve is a three-way valve. 
     
     
         15 . A shut-off valve testing system, comprising:
 a hydraulic control cylinder having an actuator volume, a return volume, and a piston therebetween;   a hydraulic actuator selectively communicating hydraulically with the actuator volume of the control cylinder, the hydraulic actuator having a loading pressure volume, an actuating pressure volume, and a piston therebetween; and   a main shut-off valve communicating with the hydraulic actuator, the main shut-off valve being installed in series in a combustible gas delivery line.   
     
     
         16 . The shut-off valve testing system according to  claim 15 , further comprising a differential pressure transmitter communicating with the actuator and return volumes of the control cylinder. 
     
     
         17 . The shut-off valve testing system according to  claim 16 , further comprising a computerized control system communicating electronically with the differential pressure transmitter. 
     
     
         18 . The shut-off valve testing system according to  claim 15 , further comprising a closure limit switch, an open limit switch, and a partial travel limit switch disposed between the hydraulic actuator and the shut-off valve. 
     
     
         19 . The shut-off valve testing system according to  claim 15 , further comprising:
 a first hydraulic valve disposed between the actuator volume of the control cylinder and the hydraulic actuator;   a source of hydraulic pressure communicating with the return volume of the control cylinder;   a second hydraulic valve disposed between the source of hydraulic pressure and the return volume of the control cylinder;   a source of hydraulic pressure communicating with the loading pressure volume and the actuating pressure volume of the hydraulic actuator;   a third hydraulic valve disposed between the source of hydraulic pressure and the actuating pressure volume of the hydraulic actuator;   a hydraulic reservoir communicating with the actuating pressure volume of the hydraulic actuator;   a fourth hydraulic valve disposed between the source of hydraulic pressure and the hydraulic reservoir; and   a fifth hydraulic valve disposed between the actuating pressure volume of the hydraulic actuator and the hydraulic reservoir.   
     
     
         20 . The shut-off valve testing system according to  claim 19 , wherein:
 the hydraulic valves are electromechanical solenoid valves; and   the second hydraulic valve is a three-way valve.